Y chromosome polymorphisms may contribute to an increased risk of male-induced unexplained recurrent miscarriage

Impacts of male chromosomal polymorphisms on semen quality and IVF/ICSI outcomes: A retrospective cohort study

OBJECTIVE

The study aims to elucidate the impacts of different types of male chromosomal polymorphisms (MCPs) on various outcomes of in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) treatment.

METHODS

This retrospective cohort study included 1442 couples with normal karyotypes, 1442 couples with MCPs, 42 couples with male chromosomal rearrangements (MCRs), and 42 couples with MCRs combined with MCPs who underwent IVF/ICSI treatment at Peking University Third Hospital from 2015 to 2021. The semen quality, embryological outcomes, and clinical outcomes of different groups stratified by karyotypes were compared.

RESULTS

For couples undergoing IVF, male inv(9) was associated with a significantly lower sperm viability rate (29.41% vs 34.49%, P = 0.030), a lower progressive motility rate (25.13% vs 30.50%, P = 0.013), and a lower normal fertilization rate (52.41% vs 59.84%, P = 0.014). Male 9qh + was related to a lower sperm viability rate (27.56% vs 34.49%, P = 0.028). No MCPs were observed to compromise clinical outcomes in couples undergoing IVF. For couples undergoing ICSI, no MCPs exhibited an association with poorer semen quality and embryological outcomes. However, Yqh + and DGpstk+ were found to be significantly correlated with an increased likelihood of preterm birth (23.3% vs 9.2%, P = 0.003; 20.0% vs 9.2%, P = 0.041, respectively). In couples with MCRs, the presence of MCPs significantly reduced the sperm viability rate (19.99% vs 30.97%, P = 0.017) and progressive motility rate (8.07% vs 27.85%, P = 0.018).

CONCLUSION

Our study provides detailed evidence for the impacts of various MCPs on IVF/ICSI outcomes, reveals the complexity and heterogeneity of these impacts, and highlights the adverse effects of male inv(9).

Diverse impacts of female chromosomal polymorphisms on assisted reproduction outcomes: a retrospective cohort study

BACKGROUND

The effects of female chromosomal polymorphisms (FCPs) on various aspects of reproductive health have been investigated, yet the findings are frequently inconsistent. This study aims to clarify the role of FCPs on the outcomes of in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI).

METHODS

This retrospective cohort study comprised 951 couples with FCPs and 10,788 couples with normal karyotypes who underwent IVF/ICSI treatment at Peking University Third Hospital between 2015 and 2021. The exposure was FCPs. The embryological outcomes and clinical outcomes were compared.

RESULTS

The FCPs, as a whole, compromised the oocyte maturation rate (76.0% vs. 78.8%, P = 0.008), while they did not adversely affect other IVF/ICSI outcomes. Further detailed analyses showed that every type of FCPs contributed to the lower oocyte maturation rate, particularly the rare FCPs (69.0% vs. 78.8%, P = 0.008). The female qh + was associated with a higher normal fertilization rate (63.0% vs. 59.2%, adjusted P = 0.022), a higher clinical pregnancy rate (37.0% vs. 30.7%, adjusted P = 0.048), and a higher live birth rate (27.0% vs.19.0%, adjusted P = 0.003) in couples undergoing IVF. Conversely, in couples undergoing ICSI, female qh + was found to be related to a lower normal fertilization rate (58.8% vs. 63.8%, P = 0.032), a comparable clinical pregnancy rate (25.7% vs. 30.9%, P = 0.289), and a comparable live birth rate (19.8% vs. 19.2%, P = 0.880) compared to the control group. Additionally, an increased risk of preterm birth was observed in women undergoing IVF with multiple polymorphisms (62.5% vs. 16.9%, adjusted P <  0.001) and in women undergoing ICSI with pstk+ (36.4% vs. 15.4%, P = 0.036).

CONCLUSIONS

Our research unravels the diverse impacts of various FCPs on IVF/ICSI outcomes, highlighting the detrimental effects of FCPs on oocyte maturation and the risk of preterm birth.

Y chromosome polymorphisms contribute to an increased risk of non-obstructive azoospermia: a retrospective study of 32,055 Chinese men

PURPOSE

To investigate the prevalence of Y chromosome polymorphisms in Chinese men and analyze their associations with male infertility and female adverse pregnancy outcomes.

METHODS

The clinical data of 32,055 Chinese men who underwent karyotype analysis from October 2014 to September 2019 were collected. Fisher's exact test, chi-square test, or Kruskal-Wallis test was used to analyze the effects of Y chromosome polymorphism on semen parameters, azoospermia factor (AZF) microdeletions, and female adverse pregnancy outcomes.

RESULTS

The incidence of Y chromosome polymorphic variants was 1.19% (381/32,055) in Chinese men. The incidence of non-obstructive azoospermia (NOA) was significantly higher in men with the Yqh- variant than that in men with normal karyotype and other Y chromosome polymorphic variants (p < 0.050). The incidence of AZF microdeletions was significantly different among the normal karyotype and different Y chromosome polymorphic variant groups (p < 0.001). The detection rate of AZF microdeletions was 28.92% (24/83) in the Yqh- group and 2.50% (3/120) in the Y ≤ 21 group. The AZFb + c region was the most common AZF microdeletion (78.57%, 22/28), followed by AZFc microdeletion (7.14%,2/28) in NOA patients with Yqh- variants. There was no significant difference in the distribution of female adverse pregnancy outcomes among the normal karyotype and different Y chromosome polymorphic variant groups (p = 0.528).

CONCLUSIONS

Patients with 46,XYqh- variant have a higher incidence of NOA and AZF microdeletions than patients with normal karyotype and other Y chromosome polymorphic variants. Y chromosome polymorphic variants do not affect female adverse pregnancy outcomes.

Recurrent miscarriage and male factor infertility: diagnostic and therapeutic implications. A narrative review

Introduction

Recurrent miscarriage is defined as 2 or more failed clinical pregnancies, typically known as repeated pregnancy loss, occurring before 20 gestational weeks, and further categorized into primary and secondary types. It represents a common and distressing condition to deal with in the field of reproductive medicine, usually affecting <5% of couples, with up to 50% of cases lacking a clearly defined aetiology. The epidemiology also varies depending on maternal age. Remarkably, the situation significantly afflicts expecting parents, whereas maternal factors, such as age and previous pregnancy loss rate, are commonly reported as risk factors. Although previously underestimated, existing evidence suggests the male factor is a possible cause of recurrent pregnancy loss.

Material and methods

A non-systematic literature review was conducted in the PubMed and Scopus databases for articles written in English investigating the possible association of the male factor in recurrent pregnancy loss. The eligible studies were synthesized in a narrative review format upon discussion and consensus among the authors after being previously independently assessed and selected.

Results

Lifestyle, obesity, genetic predisposition, chromosomal anomalies, endocrine dysfunction, anatomical abnormalities, immunological factors, infections, and oxidative stress can result in poor embryo development and recurrent miscarriage. Although professional organizations currently recognize male gender as a possible risk factor, specific recommendations on the diagnostic and therapeutic field are still lacking, and the condition necessitates a high level of suspicion and case-by-case management.

Conclusions

In this review, we delve deeper into the contribution of the male factor in the concept of recurrent miscarriage.

Analysis of Aneuploidy Rate and Pregnancy Outcomes in Unexplained Recurrent Pregnancy Loss Couples With Chromosome Polymorphism After PGT-A

Purpose

The study aims to investigate whether chromosomal polymorphism affects embryo development and pregnancy outcomes of unexplained recurrent pregnancy loss (uRPL) couples undergoing PGT-A.

Methods

A total of 585 couples with uRPL history who performed PGT-A were included in the retrospective study from January 2016 to December 2020. We included 415 couples with normal karyotype and 170 couples with chromosomal polymorphism. Furthermore, the polymorphism group was divided into two subgroups: 113 couples in the male group and 57 couples in the female group. The embryo development and pregnancy outcomes were analyzed in different groups.

Results

The blastocyst rate and aneuploidy rate are statistically different in the normal group, male polymorphism group, and female polymorphism group. Compared with normal and female groups, the male group has a lower blastocyst rate, which is statistically different (48.3 vs. 53.9%, p = 0.003; 48.3 vs. 54.1%, p = 0.043). Moreover, the aneuploidy rate of the male polymorphism group is significantly higher than female carriers (29.5 vs. 18.6%, p = 0.003). However, there were no statistically significant differences in clinical pregnancy rate, early miscarriage rate, and live birth rate after PGT-A (p &gt; 0.05).

Conclusion

Male with chromosome polymorphism (CPM) have a lower blastocyst rate and a higher aneuploidy rate than female carriers in uRPL couples undergoing PGT-A. However, when a euploid blastocyst was first transferred, no difference in pregnancy outcomes was found between the male and female polymorphism carriers. It indicated that CPM may have an adverse effect on the embryos of male carriers with uRPL history, and the occurrence of uRPL may be decreased in male polymorphism carriers after PGT-A.

Cytogenetic analysis of 3387 umbilical cord blood in pregnant women at high risk for chromosomal abnormalities

Background

Cordocentesis in our practice is most commonly indicated for rapid karyotyping in the second or third trimester and is regarded as the gold standard for foetal chromosomal aberration diagnosis in pregnancies at high risk for chromosomal abnormalities. In this study, we investigated 3387 umbilical cord blood samples for karyotyping from pregnant women who underwent cordocentesis and explored the pregnancy outcomes of foetal sex chromosome mosaicism and chromosomal polymorphism.

Results

Out of the 3387 samples, 182 abnormal karyotypes were detected. Ultrasound soft markers were the most common prenatal diagnostic indication, but the detection rate of abnormal karyotypes was 2.02%, while it was 46.97% in the genome-wide NIPT-positive group. The rate of aneuploidy was lower in the soft marker group than in the other groups. Out of 16 cases with sex chromosome mosaicism, three pregnant women with foetuses with a lower proportion of sex chromosome mosaicism delivered healthy foetuses; the foetus with karyotype 46,X,i(Y)(q10)[20]/45,X[6] showed unclear genitals. Three foetuses with chromosomal polymorphisms had postnatal disorders.

Conclusions

NIPT should not be recommended as the first-tier screening for chromosomal aberration for pregnancies with ultrasound soft markers or pathological ultrasound findings, but NIPT can be considered an acceptable alternative for pregnancies with contraindications to cordocentesis or the fear of procedure-related foetal loss. Mosaicism found in amniotic fluid cell culture requires further cordocentesis for karyotype confirmation, and the continuation of pregnancy is safe when a normal karyotype is identified in foetal blood culture. Further genetic testing and parental karyotype analysis are needed for foetal chromosomal polymorphisms.

Multi-institutional experience of genetic diagnosis in Ecuador: National registry of chromosome alterations and polymorphisms

BACKGROUND

Detection of chromosomal abnormalities is crucial in various medical areas; to diagnose birth defects, genetic disorders, and infertility, among other complex phenotypes, in individuals across a wide range of ages. Hence, the present study wants to contribute to the knowledge of type and frequency of chromosomal alterations and polymorphisms in Ecuador.

METHODS

Cytogenetic registers from different Ecuadorian provinces have been merged and analyzed to construct an open-access national registry of chromosome alterations and polymorphisms.

RESULTS

Of 28,806 karyotypes analyzed, 6,008 (20.9%) exhibited alterations. Down syndrome was the most frequent autosome alteration (88.28%), followed by Turner syndrome (60.50%), a gonosome aneuploidy. A recurrent high percentage of Down syndrome mosaicism (7.45%) reported here, as well as by previous Ecuadorian preliminary registries, could be associated with geographic location and admixed ancestral composition. Translocations (2.46%) and polymorphisms (7.84%) were not as numerous as autosomopathies (64.33%) and gonosomopathies (25.37%). Complementary to conventional cytogenetics tests, molecular tools have allowed identification of submicroscopic alterations regions or candidate genes which can be possibly implicated in patients' symptoms and phenotypes.

CONCLUSION

The Ecuadorian National Registry of Chromosome Alterations and Polymorphisms provides a baseline to better understand chromosomal abnormalities in Ecuador and therefore their clinical management and awareness. This data will guide public policy makers to promote and financially support cytogenetic and genetic testing.

C-banding and AgNOR-staining were still effective complementary methods to indentify chromosomal heteromorphisms and some structural abnormalities in prenatal diagnosis

BACKGROUND

In prenatal diagnosis, CMA has begun to emerge as a favorable alternative to karyotype analysis, but it could not identify balanced translocations, triploidies, inversion and heteromorphisms. Therefore, conventional cytogenetic and specific staining methods still play an important role in the work-up of chromosome anomaly. This study investigated the application of C-banding and AgNOR-staining techniques in prenatal diagnosis of chromosomal heteromorphisms and some structure abnormalities.

RESULTS

Among the 2970 samples, the incidence of chromosomal heteromorphisms was 8.79% (261/2970). The most frequent was found to be chromosome Y (2.93%, 87/2970), followed by chromosome 1 (1.65 %, 49/2970), 9 (1.52 %, 45/2970), 22 (0.77 %, 23/2970) and 15 (0.64 %, 19/2970). We compared the incidence of chromosomal heteromorphisms between recurrent spontaneous abortion (RSA) group and control group. The frequency of autosomal hetermorphisms in RSA group was 7.63% higher than that in control group (5.78%), while the frequency of Y chromosomal heteromorphisms was 4.76% lower than that in control group (5.71%). Here we summarized 4 representative cases, inv (1) (p12q24), psu dic (4;17) (p16.3;p13.3), r(X)(p11; q21) and an isodicentric bisatellited chromosome to illustrate the application of C-banding or AgNOR-staining, CMA or NGS was performed to detect CNVs if necessary.

CONCLUSIONS

This study indicated that C-banding and AgNOR-staining were still effective complementary methods to identify chromosomal heteromorphisms and marker chromosomes or some structural rearrangements involving the centromere or acrocentric chromosomes. Our results suggested that there was no evidence for an association between chromosomal heteromorphisms and infertility or recurrent spontaneous abortions. Undoubtedly, sometimes we needed to combine the results of CMA or CNV-seq to comprehensively reflect the structure and aberration of chromosome segments. Thus, accurate karyotype reports and genetic counseling could be provided.

Chromosomal polymorphisms are independently associated with multinucleated embryo formation

PURPOSE

The purpose of this study is to explore the factors associated with embryo multinucleation, particularly focused on the influence of parental chromosomal polymorphisms in embryo multinucleation.

METHODS

This is a retrospective case-control study involving 1260 infertile couples undergoing their first IVF/ICSI cycles. Couples were screened for abnormalities in their karyotype and were evaluated for blastomere persistence of multinucleation. Demographic characteristics, stimulation protocol, and pregnant outcomes were analyzed using logistic regression analysis.

RESULTS

The level of basal FSH was lower in the multinucleated embryos group (5.37 vs 5.72 IU/L). The Multinucleated embryos group received less gonadotropins (1788.5 vs 1891.3 IU), and the level of LH on day of HCG triggering was lower (1.09 vs 1.30 IU/L). More oocytes were recovered in the multinucleated embryos group (11.51 vs 9.23). Chromosomal polymorphisms were seen in at least 1 out of 163 (12.9%) couples. Multivariate logistic regression analysis revealed that chromosomal polymorphisms were independently associated with an increase in the occurrence risk of multinucleated embryos (OR = 1.61, 95% CI, 1.06-2.44) in the first IVF/ICSI cycle. The miscarriage rate in the multinucleated embryos group was 10% higher than that of the control group.

CONCLUSIONS

Chromosomal polymorphisms were independently associated with multinucleation embryo formation. A higher LH level on the day of HCG triggering was associated with a decreased chance of multinucleation.